DIAGNOSIS FUNCTION


ENGINE WARNING LAMP (CHECK ENGINE LAMP)

If an abnormality occurs in any of the following items related to the Multipoint Fuel Injection (MPI) system, the engine warning lamp will illuminate.
If the lamp remains illuminated or if the lamp illuminates while the engine is running, check the diagnosis code output.

ENGINE WARNING LAMP INSPECTION ITEMS
Code No.
 Diagnosis item
-
 Engine-ECU <M/T> or engine-A/T-ECU <A/T>
P0102*
 Air flow sensor circuit low input
P0103*
 Air flow sensor circuit high input
P0107
 Manifold absolute pressure sensor circuit low input
P0108
 Manifold absolute pressure sensor circuit high input
P0112*
 Intake air temperature sensor circuit low input
P0113*
 Intake air temperature sensor circuit high input
P0117*
 Engine coolant temperature sensor circuit low input
P0118*
 Engine coolant temperature sensor circuit high input
P0122*
 Throttle position sensor (main) circuit low input
P0123*
 Throttle position sensor (main) circuit high input
P0125*
 Insufficient coolant temperature for closed loop fuel control
P0130
 Oxygen sensor circuit <vehicles with catalytic converter>
P0131
 Oxygen sensor circuit low voltage <vehicles with catalytic converter>
P0132
 Oxygen sensor circuit high voltage <vehicles with catalytic converter>
P0135
 Oxygen sensor heater system <vehicles with catalytic converter>
P0201
 No. 1 injector system
P0202
 No. 2 injector system
P0203
 No. 3 injector system
P0204
 No. 4 injector system
P0205
 No. 5 injector system
P0206
 No. 6 injector system
P0222*
 Throttle position sensor (sub) circuit low input
P0223*
 Throttle position sensor (sub) circuit high input
P0300*
 Ignition coil (power transistor) system
P0335*
 Crank angle sensor system
P0340*
 Camshaft position sensor system
P0403
 Exhaust gas recirculation control system
P0500
 Vehicle speed sensor system
P0603*
 EEPROM malfunction
P0606*
 Engine-ECU <M/T> or engine-A/T-ECU <A/T> main processor malfunction
P0638*
 Throttle valve control servo circuit range/performance problem
P0642*
 Throttle position sensor power supply
P0657*
 Throttle valve control servo relay circuit malfunction
P1602*
 Communication malfunction (between engine-ECU <M/T> or engine-A/T-ECU <A/T> main processor and system LSI)
P1603*
 Battery backup circuit malfunction
P2100*
 Throttle valve control servo circuit (open)
P2101*
 Throttle valve control servo magneto malfunction
P2122*
 Accelerator pedal position sensor (main) circuit low input
P2123*
 Accelerator pedal position sensor (main) circuit high input
P2127*
 Accelerator pedal position sensor (sub) circuit low input
P2128*
 Accelerator pedal position sensor (sub) circuit high input
P2135*
 Throttle position sensor (main and sub) range/performance problem
P2138*
 Accelerator pedal position sensor (main and sub) range/performance problem
P2228*
 Barometric pressure sensor circuit low input
P2229*
 Barometric pressure sensor circuit high input
U1108*
 Combination meter time-out
note After the engine-ECU <M/T> or engine-A/T-ECU <A/T> has detected a malfunction, the engine warning lamp illuminates when the engine is next turned on and the same malfunction is re-detected. However, for items marked with a "*" in the diagnosis code number column, the engine warning lamp illuminates only on the first detection of the malfunction.

METHOD OF READING AND ERASING DIAGNOSIS CODES
Refer to , GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions.

DIAGNOSIS USING DIAGNOSIS 2 MODE (INCREASED SENSITIVITY)

  1. Switch the diagnosis mode of the engine control unit to DIAGNOSIS 2 mode using the M.U.T.-III.
  2. Carry out a road test.
  3. Take a reading of the diagnosis code and repair the problem location.
  4. Turn the ignition switch to OFF and then back to ON again.
    note By turning the ignition switch to OFF, the engine-ECU <M/T> or engine-A/T-ECU <A/T> will switch the diagnosis mode from DIAGNOSIS 2 mode to DIAGNOSIS 1 mode.
  5. Erase the diagnosis codes.

INSPECTION USING M.U.T.-III DATA LIST AND ACTUATOR TESTING
1.Carry out inspection by means of the data list and the actuator test function, if there is an abnormality, check and repair the chassis harness and components.
2.After repairing, re-check using the M.U.T.-III and check that the abnormal input and output have returned to normal as a result of the repairs.
3.Erase the diagnosis code memory.
4.Remove the M.U.T.-III, and then start the engine again and carry out a road test to confirm that the problem has disappeared.

FREEZE FRAME DATA
When the engine-ECU <M/T> or engine-A/T-ECU <A/T> detects a malfunction and stores a diagnosis code, it also stores a current status of the engine. This function is called "Freeze frame data". By analyzing this "Freeze frame" data with the M.U.T.-III, an effective troubleshooting can be performed.
The display items of freeze frame data are shown below.

DISPLAY ITEM LIST
Item No.
 Data
 Unit/Condition
AA*1
 Air flow sensor
 g/s
AB*1
 Throttle position sensor (main)
 %
AC*1
 Oxygen sensor <vehicles with catalytic converter>
 V
BA*1
 Target exhaust gas recirculation
 %
BB*1
 Barometric pressure sensor
 kPa
BC*1
 Relative throttle position sensor
 %
BD*1
 Throttle position sensor (sub)
 %
BE*1
 Accelerator pedal position sensor (main)
 %
BF*1
 Accelerator pedal position sensor (sub)
 %
C0*1
 Fuel control condition 1 <vehicles with catalytic converter>
  • CL (closed loop)*2
  • OL (open loop)*3
  • OL-DRV. (open loop depending on the drive condition)*4
  • OL-SYS. (open loop due to system abnomaly)*5
C2*1
 Calculated load value
 %
C3*1
 Engine coolant temperature sensor
 °C
C4*1
 Short term fuel compensation 1
 %
C6*1
 Long term fuel compensation 1
 %
CC*1
 Manifold absolute pressure sensor
 kPa
CD*1
 Crank angle sensor
 r/min
CE*1
 Vehicle speed signal
 km/h
CF*1
 Advance ignition
 °CA
D0*1
 Intake air temperature sensor
 °C
D1*1
 Time since engine running*6
 sec
D6*1
 Purge solenoid duty
 %
D8*1
 Power supply voltage
 V
D9*1
 Absolute load value
 %
DA*1
 Target equivalence ratio
 -
DB*1
 Intake air temperature sensor
 °C
DC*1
 Commanded throttle actuator control
 %
note *1: The items of Freeze Frame Data can be seen by selecting "Freeze Frame Data (OBD)" on "Self-diagnosis" screen of M.U.T.-III. When system malfunctions are detected, the first detected malfunction data only is stored.
note *2: Condition in which oxygen sensor signals are fed back to the engine-ECU <M/T> or engine-A/T-ECU <A/T> for controlling fuel.
note *3: Condition in which fuel is controlled without oxygen sensor signals being fed back to the engine-ECU <M/T> or engine-A/T-ECU <A/T> because the condition to shift to the closed loop is not met.
note *4: Condition of open loop due to acceleration and deceleration driving.
note *5: Condition of open loop due to system failure.
note *6: Time between engine start and malfunction detection.

FAIL-SAFE FUNCTION REFERENCE TABLE


When the main sensor malfunctions are detected by the diagnosis function, the vehicle is controlled by means of the pre-set control logic to maintain safe conditions for driving.
Malfunctioning item
 Control contents during malfunction
Air flow sensor
  • Reads the injector basic drive time and basic ignition timing from the preset map using throttle position sensor signals and engine speed signals (crank angle sensor signals).
  • Does not control idle speed.
Intake air temperature sensor
 Controls as if the intake air temperature is 25°C.
Barometric pressure sensor
 Controls as if the barometric pressure is 101 kPa.
Engine coolant temperature sensor
 Controls as if the engine coolant temperature is 80°C. (This control will be continued until the ignition switch is turned to the "LOCK" (OFF) position even though the sensor signal returns to normal.)
Camshaft position sensor
  • The control condition before the fail is determined is continued.
  • After 4 seconds pass from when the malfunction is detected, the fuel is shut off. (After the ignition switch is turned to ON position, the No.1 cylinder top dead center is no detected at all.)
Oxygen sensor <vehicles with catalytic converter>
 Does not control air-fuel ratio closed loop.
Injector
 Does not control exhaust gas recirculation.
Manifold absolute pressure sensor
  • Does not correct the injector drive time corresponding to inlet manifold vacuum pressure.
  • Does not control exhaust gas recirculation.
Throttle position sensor (main)
  • Controls the throttle valve position through the use of the throttle position sensor (sub) signal.
  • Renders the amount of accelerator pedal travel as being approximately one-half the normal opening angle.
  • Prohibits the operation of the engine speed feedback control.
  • Cuts off fuel when the engine speed exceeds 3,000 r/min.
  • Suppresses the engine output by stopping the electronic-controlled throttle valve system if the throttle position sensor (sub) is also malfunctioning.
Accelerator pedal position sensor (main)
  • Detects the amount of the accelerator pedal travel through the use of the accelerator pedal position sensor (sub) signal, but rendering it only as being approximately one-half the normal opening angle.
  • Cuts off fuel when the engine speed exceeds 3,000 r/min.
  • Suppresses the engine output by stopping the electronic-controlled throttle valve system if the accelerator pedal position sensor (sub) is also malfunctioning.
Throttle position sensor (sub)
  • Controls the throttle valve position through the use of the throttle position sensor (main) signal.
  • Renders the amount of accelerator pedal travel as being approximately one-half the normal opening angle.
  • Cuts off fuel when the engine speed exceeds 3,000 r/min.
  • Suppresses the engine output by stopping the electronic-controlled throttle valve system if the throttle position sensor (main) is also malfunctioning.
Accelerator pedal position sensor (sub)
  • Detects the amount of the accelerator pedal travel through the use of the accelerator pedal position sensor (main) signal, but rendering it only as being approximately one-half the normal opening angle.
  • Cuts off fuel when the engine speed exceeds 3,000 r/min.
  • Suppresses the engine output by stopping the electronic-controlled throttle valve system if the accelerator pedal position sensor (main) is also malfunctioning.
Throttle valve control microcomputer
  • Suppresses the engine output by stopping the electronic-controlled throttle valve system.
  • Prohibits the operation of the engine speed feedback control.
Throttle valve control servo
  • Suppresses the engine output by stopping the electronic-controlled throttle valve system.
  • Prohibits the operation of the engine speed feedback control.
Throttle valve position feedback
  • Suppresses the engine output by stopping the electronic-controlled throttle valve system.
  • Prohibits the operation of the engine speed feedback control.
Communication between throttle valve control microcomputer and engine control microcomputer
  • Renders the amount of accelerator pedal travel as being approximately one-half the normal opening angle.
  • Prohibits the operation of the engine speed feedback control.
  • Cuts off fuel when the engine speed exceeds 3,000 r/min.
Detonation sensor
 The ignition timing is set having enough time against knocking.
Ignition coil, power transistor
 Shuts off fuel injection to misfiring cylinders.
Alternator FR terminal
 Does not control the output of the alternator according to an electrical load. (works as a normal alternator)